This study is prospective, randomized, double-blinded and controlled. A total of 60 subjects will be randomly assigned to one of three treatment arms of the study: 20 subjects into the 1.5 atm abs oxygen equivalent HBO2 treatment, 20 subjects into the 2.0 atm abs oxygen equivalent HBO2 treatment and 20 subjects into the sham treatment (a placebo exposure equivalent to breathing atmospheric air). The protocol utilizes a pre- and post-treatment comprehensive performance battery that will allow for meaningful clinical outcomes and a broad understanding of the effects of the treatment. This project represents a collaboration between the Department of Defense (DoD), the Richmond Veterans Administration Medical Center (VAMC) and Virginia Commonwealth University. Service members will be recruited from military bases/treatment facilities (MTF), receive hyperbaric oxygen at existing DoD hyperbaric chambers and be evaluated by the established Virginia Commonwealth University-Center for Rehabilitation Sciences and Engineering (CERSE), a collaborative research center co-located at the Richmond VAMC and VCU.